Electron discharge tube



23,1931. G, HQLST Y 1,811,051

' snscmon mscnnas TUBE rued oct. 28'. 1924 Patented June 23, l,

- 'SUNljTEDjsr-ATES PATENT OFFICE Gm HOLST, OFmHOvEN, N'ET, .ASSIGNQR T0 N. VaPHILIPS otoninmmenmaxnn, or EINDHOVEN mamon mscnnnon TUBE Anuman-mea october as, 1994,- seriai No. 746,396, and m Germany november 27, 192s. f

This invention has reference to an improved discharge tube comprising an incan- ,descent cathode,.an anode and a controlling grid and has for its object the use of a cathode consistin of material that, at a temrature materia y lower thanis necessar resent invention or a cathode made of tungsten, emits a su a space-charge grid ma es the curve again iicient -quantity, 'of electrons for operating more inclined;

the tube, in combination with one or more auxiliary electrodes provided in the tube in Way of example some embodiments of the addition to the controlling id.l Many materials may be use for constituting at least part of the surface of the cathode 1n order to allow the latter to emit'atan approximately low temperature a; numberof electrons suflicient for the operation of the tube. .As suitable materials for exam invention.

been mentioned, which at Aa tem erature of anode-SCI'GGIL about 1300-1380 K. emits a num er of electrons equal to that emitted by tungsten towards 2000 -K. It has also been su gested to coat. the surface of the cath e with compounds of earth alkalies and more ially -withtheir oxides.

t is known, moreover, to providel the disarge tube with one or more grids in"addi' tlon to the. controlling grid. Such a grid The accompanying drawings illustrate, by

. o Figure'l is an elevation pa/rtly -in section of a tube provided with a's'pace-.charge grid. Figure 2 shows the electrodes and the leading-in wires of a tube comprising an anode-screen with their supports.` J le, Figure 3 illustrates a l"construction of a thorium or a compound o thorium has tube comprising a space-charge grid and anl The drawings show the exhausted glass envelope l of a tube comprising aglass stem 2, the leading-in wires and the supports being sealed in the latter in the usual manner. The anode-is indicated in the fi ures by the reference numeral 3 and a helica 'controlling grid by the reference numeral 4. In the constructions illustrated the two cylindrical electrodes .3 and 4 are arranged concentri-Y.

ma for' exam le, be arranged near the cally around the straight cathode -5'as their 0 ca ode in or er to sup ress the space axis. The said catho charge, or near the anode morder to serve as -an anode-screen. The use of the said" grids and more especially. of the spacecharge id allows a material reduction in n the ano e tension of a three-electrode tube, in comparison` with the tension of a.v tube without a space charge grid, if the twotubes are otherwise in -the same condition.

The invention has `the' advanta e thatthe 9 tensions which haveI to be supp led to the anode and to theincandescent cathode andthe consumption of energycan be reduced materially m com arison with the tensions and the consumptlon of energy of a three-l .a electrode tube rovided with a cathode made e total energy re uired -for operatmg the tube, for examp e, as an erating range. amplifier inwireless telegraphy may be supplied by ve or six dry cells.A W In practice it has been found that' a v of tungsten.

e consists entirely or i partly of material yielding at the same temperature aconsiderably greater emission of 1 electrons than tungsten. For example, part of the surface'of such a cathode may be covered with oxides of earth alkalies.

The-Figures l and 3 show, in additlon to the said electrodes, a helical space-charge. grid 6, arranged near the cathode and Aservmg to suppress substantially7 the space charge which impedes the emission of the electrons in the vicinity of the cathode. The Figures 2 and 3 show constructions comprising a helical anode-screen 7, ar- -ranged near the anode in order to impart a greater inclination to the characteristic curve of the tube in the most favourable op- The said grids may besecured in any suitable manner, for example, by sealing eachv turn of the grid to a supportlngrod 11.

cathode adapted to be operatedat a low temperature renders the characteristic curve of the tube less inclined than a cathode made of tungsten and having the same current of saturation. The obviates this disadvanta e ecause especially The tube .is 'provided with `a base having a metallic cap 8, having arranged in it a contact screw -9 to which one of the leading-in wires is connected. The other leading-in wires are connected by means of conductors to the plugs 10 which maybe arrangled in an insulating plate of the cap. T e low, consumption of energy :for such a tube permits locating the cells required 10 for the operation of the tube in the little case that ordinarily contains the other devices belonging to a wireless installation.

-What I claim is:

Adischarge tube comprising a glass envelope, a base to which the envelope is sealed,

a press supported by said base, a straight ila'mentary cathode perpendicular to the .direction of the press, a c lindrical control grid mounted about the lament as axis, a 2o cylindrical plate concentric with the Vcontrol grid, an auxiliary cylindrical grid between the filament and the control grid, a second auxiliary cylindrical rid mounted between the control grid and t e anode, prongs projecting downwardly fromsaid base, an additional terminal on the base, alead from one of the electrodes to said terminal, and leads from the remaining electrodes to the prongs.

In testimony whereof I aiix my signature `30 at the city of Eindhoven, this 22nd day ci d September, 1924. l

, GILLES HOLS'Ipt- 

